This invention relates to a technology of managing data paths in a storage system, in particular, detecting a fault site in an externally-connected storage system upon occurrence of a fault and switching paths therein.
For example, JP 2007-257667 A discloses a technology of so-called storage system external-connection, in which a first storage system connected to a computer is further connected to a second storage system and provides the computer with a physical storage area of the second storage system as a virtual storage area of the first storage system. According to such external-connection, a function included in the first storage system can also be applied to the storage area of the second storage system.